Peroxo group enhanced nanorutile as visible light active photocatalyst

Associating low crystallinity with peroxo groups for enhanced visible light active photocatalysts

“…It was also observed, that sensitizing titania with dyes or modifying it using hydrogen peroxide resulted in better photocatalytic activities compared to reference commercial TiO 2 -s in case of visible light irradiation, although the most prominent increase in activity was noticed in case of hydrogen peroxide, which was attributed to the formation of peroxo chelate complexes resulting in decreased particle sizes. The advantages of applying hydrogen peroxide during the synthesis was also observed in our previous study [34], in which a relatively novel approach was applied to enhance the visible light excitability of rutile titania by anchoring peroxo groups onto the surface. Since anatase is considered to be more active for photocatalytic applications [33], in this study our recent synthesis method was modified to obtain anatase titania and further attempts were made to sensitize the catalystthus enhancing its visible light excitabilityin a facile, costeffective way.…”

“…There are numerous instances in the literature that by applying different approaches (e.g. doping, deposition of noble metals) successful enhancement of visible light excitability was observed which corresponded well with the resulting photocatalytic efficiency [12,14,34,45]. Presumably, the greatly enhanced visible light excitability of pH3_55 and pH3_70 peroxo-titania will be beneficial for the photocatalytic efficiency.…”

“…The photocatalytic efficiencies were determined using phenol (Spektrum 3D; analytical grade) as model contaminant. As reference photocatalysts self-made 'Rutile-H2′ TiO 2 (which is a peroxo group containing rutile TiO 2 with high visible light excitability, published in our recent work [34]) and commercial Evonik Aeroxide P25, Sigma-Aldrich anatase and Sigma-Aldrich rutile were used.…”

“…The preparation of the peroxo-titania was based on our recent synthesis method [34] in which it was found that in order to anchor peroxo groups on the surface the n Ti :n H2O2 ratio has to be set to 1:2 (resulting the 'Rutile-H2′ TiO 2 ). The possible cause of this phenomenon and the different forms of peroxo complexes in case of different pH conditions were discussed in detail in our previous work [34], and in other scientific publication as well [35]. Considering the above-mentioned reaction parameters, the synthesis was carried out as follows.…”

“…1c) in case of pH3_55, pH3_70 peroxo-titania. Compared to Rutile-H2 TiO 2 (characterized in our recent publication [34]), similarly, the broad band centered at 3400 cm −1 and the sharp band at 1630 cm −1 can be detected, which represent the stretching and bending vibrations of surface OH groups [46,47], and the small peak at 2357 cm −1 representing bonds containing carbon [46,48,49] can be attributed either to adsorbed CO 2 or residual contamination from the TiO 2 precursor. At 900 cm −1 a new peak was observed, which can be attributed either to free or complexed -OeO-vibrations [49,50] or the vibration of TieO bonds within the triangular peroxy titanyl group [48,51,52].…”